1. Field of the Invention
Apparatuses and methods consistent with the exemplary embodiments of the present invention relate to a wideband digitally-controlled oscillator (DCO) and a digital broadcasting receiver having the same, and more particularly, to a wideband digitally-controlled oscillator which not only occupies less space but also operates within a wideband frequency range and a digital broadcasting receiver having the same.
2. Description of the Related Art
A general phase-locked loop (PLL) is used to obtain a signal having fixed phase and frequency by detecting and adjusting variation of the phase and frequency.
Recently, a digital PLL has been widely used, and a digitally controlled oscillator (DCO) is used for the digital PLL.
A related-art DCO is based on an LC oscillator and thus obtains oscillation frequency with reference to inductance L and capacitance C as in Equation 1.
                    f        =                  1                      2            ⁢                                                  ⁢            π            ⁢                          LC                                                          [                  EQN          .                                          ⁢          1                ]            
That is, a related-art DCO based on an LC oscillator tunes oscillation frequency by varying capacitance or inductance.
However, if a single DCO is used, the range of operating frequency is limited. In order to implement a wideband DCO according to a related-art method, a plurality of DCOs having different operating frequency ranges, including a first DCO operating from 1 GHz to 2 GHz, a second DCO operating from 2 GHz to 3 GHz, and a third DCO operating from 3 GHz to 4 GHz, are arranged in an array structure, each DCO is selected suitable for the operating frequency, and thus a wideband DCO having operating frequency ranging from 1 GHz to 4 GHz is implemented.
The wideband DCO having the above feature uses a plurality of DCOs operating in different operating frequencies. Therefore, although operating frequency is adjusted by varying capacitance while inductance is fixed, the wideband DCO should include a plurality of inductors.
If a wideband DCO is fabricated in a form of a single integrated circuit (IC) chip, inductors occupies most of the IC chip. Accordingly, it is difficult to miniaturize the size of IC chip using a related-art method.